RV-pulmonary arterial coupling predicts outcome in patients referred for pulmonary hypertension.

Objective: Prognosis in pulmonary hypertension (PH) is largely determined by RV function. However, uncertainty remains about what metrics of RV function might be most clinically relevant. The purpose of this study was to assess the clinical relevance of metrics of RV functional adaptation to increased afterload.

Gleaning knowledge from data in the intensive care unit.

It is often difficult to accurately predict when, why, and which patients develop shock, because signs of shock often occur late, once organ injury is already present. Three levels of aggregation of information can be used to aid the bedside clinician in this task: analysis of derived parameters of existing measured physiologic variables using simple bedside calculations (functional hemodynamic monitoring); prior physiologic data of similar subjects during periods of stability and disease to define quantitative metrics of level of severity; and libraries of responses across large and comprehensive collections of records of diverse subjects whose diagnosis, therapies, and course is already known to predict not only disease severity, but also the subsequent behavior of the subject if left untreated or treated with one of the many therapeutic options. The problem is in defining the minimal monitoring data set needed to initially identify those patients across all possible processes, and then specifically monitor their responses to targeted therapies known to improve outcome.

Ventriculoarterial decoupling in human septic shock.

Introduction: Septic shock is the most severe manifestation of sepsis. It is characterized as a hypotensive cardiovascular state associated with multiorgan dysfunction and metabolic disturbances. Management of septic shock is targeted at preserving adequate organ perfusion pressure without precipitating pulmonary edema or massive volume overload.

My paper 20 years later: Effect of positive end-expiratory pressure on right ventricular function in humans.

Introduction: In 1992, we published a report on the effect of positive end-expiratory pressure (PEEP) on right ventricular (RV) function in humans.

Results: We measured RV volumes and pressures and pericardial pressure (Ppc) as PEEP was increased from zero to 15 cm H20 in 12 patients after thoracotomy, using a pulmonary arterial catheter equipped with a rapid responding thermistor that allowed measurement of RV ejection fraction (RVef), while Ppc was measured via a pericardial balloon catheter. RV end-diastolic volume (EDV) was estimated as the ratio of stroke volume (SV) to RVef, whereas RV end-systolic volume (ESV) were estimated as RV EDV-SV.

Functional haemodynamic monitoring.

Purpose Of Review: Functional haemodynamic monitoring is the assessment of the dynamic interactions of haemodynamic variables in response to a defined perturbation.

Recent Findings: Fluid responsiveness can be predicted during positive pressure breathing by variations in venous return or left ventricular output using numerous surrogate markers, such as arterial pulse pressure variation (PPV), left ventricular stroke volume variation (SVV), aortic velocity variation, inferior and superior vena cavae diameter changes and pulse oximeter pleth signal variability. Similarly, dynamic changes in cardiac output to a passive leg raising manoeuvre can be used in any patient and measured invasively or noninvasively.

Rapid increase in southern elephant seal genetic diversity after a founder event.

Genetic diversity provides the raw material for populations to respond to changing environmental conditions. The evolution of diversity within populations is based on the accumulation of mutations and their retention or loss through selection and genetic drift, while migration can also introduce new variation. However, the extent to which population growth and sustained large population size can lead to rapid and significant increases in diversity has not been widely investigated.

Meta-analysis reveals lower genetic diversity in overfished populations.

While population declines can drive the loss of genetic diversity under some circumstances, it has been unclear whether this loss is a general consequence of overharvest in highly abundant marine fishes. We compiled data from 11 049 loci across 140 species and found that allelic richness was lower in overfished populations within 9 of 12 genera and families. A multiple linear regression showed that allelic richness was on average 12% lower (P < 0.

Cultivating creativity in conservation science.

Conservation practitioners and scientists are often faced with seemingly intractable problems in which traditional approaches fail. While other sectors (e.g.

Marine taxa track local climate velocities.

Organisms are expected to adapt or move in response to climate change, but observed distribution shifts span a wide range of directions and rates. Explanations often emphasize biological distinctions among species, but general mechanisms have been elusive. We tested an alternative hypothesis: that differences in climate velocity-the rate and direction that climate shifts across the landscape-can explain observed species shifts.

Model-based prediction of autoregulatory exhaustion in response to lower-body negative pressure-induced shock.

Background: We assessed the ability of a normalized autonomic nervous system (ANS) stress measure defined as an increase in the percentage of pulse rate from a baseline homeostasis state to identify corresponding changes in circulating blood volume to quantitatively recognize hypovolemia and predict subsequent autoregulatory exhaustion. Autoregulatory exhaustion is defined as the point where decreased circulatory volume exceeds the compensatory mechanism capacity to maintain flow and pressure. We derived frequency-based measures of pulse rate and pulse strength using a reflective pulse oximeter waveform of a photoplethysmograph placed on the forehead.

Effect of acute endotoxemia on analog estimates of mean systemic pressure.

Dynamic estimates of mean systemic pressure based on a Guytonian analog model (Pmsa) appear accurate under baseline conditions but may not remain so during septic shock because blood volume distribution and resistances between arterial and venous beds may change. Thus, we examined the effect of acute endotoxemia on the ability of Pmsa, estimated from steady-state cardiac output, right atrial pressure, and mean arterial pressure, to reflect our previously validated instantaneous venous return measure of mean systemic pressure (Pmsi), derived from beat-to-beat measures of right ventricular stroke volume and right atrial pressure during positive pressure ventilation. We studied 6 splenectomized pentobarbital-anesthetized close chested dogs.

Does intra-aortic balloon support for myocardial infarction with cardiogenic shock improve outcome?

Citation: Thiele H, Zeymer U, Neumann FJ, Ferenc M, Olbrich HG, Hausleiter J, Richardt G, Hennersdorf M, Empen K, Fuernau G, Desch S, Eitel I, Hambrecht R, Fuhrmann J, Böhm M, Ebelt H, Schneider S, Schuler G, Werdan K; IABP-SHOCK II Trial Investigators: Intraaortic balloon support for myocardial infarction with cardiogenic shock. N Engl J Med 2012, 367:1287-1296.

Background: In the current international guidelines, intra-aortic balloon pump (IABP) counterpulsation is considered a class I treatment for acute myocardial infarction complicated by cardiogenic shock.

Noninvasive assessment of acute dyspnea in the ED.

Background: We compared the ability of noninvasive measurements of cardiac output (CO) and thoracic fluid content (TFC) and their change in response to orthostatic challenges to diagnose acute decompensate heart failure (ADHF) from non-ADHF causes of acute dyspnea in patients in the ED.

Methods: Forty-five patients > 44 years old presenting in the ED with dyspnea were studied. CO and TFC were monitored with a NICOM bioreactance device.